{"id":"CVE-2021-35394","published":"2021-08-16T12:15:07Z","modified":"2026-06-17T03:57:29Z","title":"Realtek Jungle SDK Remote Code Execution Vulnerability","vendor":"Realtek","product":"Jungle Software Development Kit (SDK)","tier":"core","eol":null,"description":{"text":"Realtek Jungle SDK version v2.x up to v3.4.14B provides a diagnostic tool called 'MP Daemon' that is usually compiled as 'UDPServer' binary. The binary is affected by multiple memory corruption vulnerabilities and an arbitrary command injection vulnerability that can be exploited by remote unauthenticated attackers.","provenance":"source","from":"NVD"},"summary":{"text":"Realtek's Jungle Software Development Kit (SDK) versions v2.x through v3.4.14B contain multiple memory corruption flaws and an OS command injection flaw in the 'MP Daemon' diagnostic tool, usually compiled as the 'UDPServer' binary. An unauthenticated attacker with network access can exploit these flaws remotely, with no user interaction or special configuration required, to execute arbitrary commands on the affected device.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-29T13:44:44Z"},"cvss":{"score":9.8,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.99877,"percentile":0.99964,"date":"2026-10-29","provenance":"source"},"kev":{"dateAdded":"2021-12-10","dueDate":"2021-12-24","ransomware":false,"requiredAction":"Apply updates per vendor instructions.","notes":"https://nvd.nist.gov/vuln/detail/CVE-2021-35394","provenance":"source"},"vulncheckKev":{"dateAdded":"2021-08-27","exploitedFirstSeen":"2021-08-27","ransomware":false,"evidence":[{"url":"https://blogs.juniper.net/en-us/threat-research/realtek-cve-2021-35394-exploited-in-the-wild","date":"2021-08-27"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2021-12-10"},{"url":"https://blog.netlab.360.com/men-sheng-fa-da-cai-fodchajiang-shi-wang-luo/","date":"2022-04-13"},{"url":"https://web.archive.org/web/20230318134256/https://unit42.paloaltonetworks.com/network-security-trends-aug-oct-2022/","date":"2023-01-12"},{"url":"https://unit42.paloaltonetworks.com/realtek-sdk-vulnerability/","date":"2023-01-24"},{"url":"https://ti.qianxin.com/blog/articles/GooberBot:-New-Member-of%20Scar-Rental-Botnet/","date":"2023-02-10"},{"url":"https://www.fortinet.com/blog/threat-research/moobot-strikes-again-targeting-cacti-and-realtek-vulnerabilities","date":"2023-03-29"},{"url":"https://ti.qianxin.com/blog/articles/Dark-IoT-Botnet-Abuses-ClouDNS-and-White-Domains-for-C2-Communication-EN/","date":"2023-04-18"},{"url":"https://cujo.com/blog/the-2022-2023-iot-botnet-report-vulnerabilities-targeted/","date":"2023-04-27"},{"url":"https://cujo.com/the-2022-2023-iot-botnet-report-vulnerabilities-targeted/","date":"2023-04-27"}],"evidenceTotal":20,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev 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2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"},{"name":"Actively_Exploited_Kev | Oct 19, 2026","url":"https://otx.alienvault.com/pulse/6ad4dda174e5797d0bd238b7","created":"2026-10-18"},{"name":"Actively_Exploited_Kev | Oct 18, 2026","url":"https://otx.alienvault.com/pulse/6ad38c22e1848f8189d1c121","created":"2026-10-17"}],"provenance":"machine"},"cwes":[{"id":"CWE-78","name":"Improper Neutralization of Special Elements used in an OS Command"},{"id":"CWE-138","name":"Improper Neutralization of Special Elements"}],"references":[{"url":"https://www.iot-inspector.com/blog/advisory-multiple-issues-realtek-sdk-iot-supply-chain","tags":["Broken Link","Exploit","Third Party Advisory"]},{"url":"https://www.realtek.com/en/cu-1-en/cu-1-taiwan-en","tags":["Broken Link","Patch","Vendor Advisory"]},{"url":"https://www.realtek.com/images/safe-report/Realtek_APRouter_SDK_Advisory-CVE-2021-35392_35395.pdf","tags":["Patch","Vendor 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(ATT&CK 16.1); capability: Code Execution","mappingType":"exploitation_technique","evidence":[],"comment":"The vulnerability in Realtek Jungle chipsets is exploited by remote, unauthenticated attackers using UDP packets to a server on port 9034, enabling remote execution of arbitrary commands. The attack involves injecting a shell command that downloads and executes a shell script on the compromised device. This script downloads binaries for various CPU architectures, such as ARM, MIPS, and SuperH, primarily from the Mirai malware family, turning the device into a botnet node.\n\nThe attack script connects to a malicious IP to download and execute malware, with threats mainly from Mirai, Gafgyt, and Mozi families. It also includes a new DDoS botnet called RedGoBot, developed in Golang. The script uses wget and curl to download botnet clients for different processor architectures. RedGoBot can perform DDoS attacks on various protocols, including HTTP, ICMP, TCP, UDP, VSE, and OpenVPN, upon receiving commands from the threat operator. Additionally, injected commands can write binary payloads to files for execution or reboot the targeted server to cause denial of service.","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"},{"id":"T1059","name":"Command and Scripting Interpreter","tactics":["execution"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Code Execution","mappingType":"primary_impact","evidence":[],"comment":"The vulnerability in Realtek Jungle chipsets is exploited by remote, unauthenticated attackers using UDP packets to a server on port 9034, enabling remote execution of arbitrary commands. The attack involves injecting a shell command that downloads and executes a shell script on the compromised device. This script downloads binaries for various CPU architectures, such as ARM, MIPS, and SuperH, primarily from the Mirai malware family, turning the device into a botnet node.\n\nThe attack script connects to a malicious IP to download and execute malware, with threats mainly from Mirai, Gafgyt, and Mozi families. It also includes a new DDoS botnet called RedGoBot, developed in Golang. The script uses wget and curl to download botnet clients for different processor architectures. RedGoBot can perform DDoS attacks on various protocols, including HTTP, ICMP, TCP, UDP, VSE, and OpenVPN, upon receiving commands from the threat operator. Additionally, injected commands can write binary payloads to files for execution or reboot the targeted server to cause denial of service.","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"},{"id":"T1071.001","name":"Web Protocols","tactics":["command-and-control"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Code Execution","mappingType":"secondary_impact","evidence":[],"comment":"The vulnerability in Realtek Jungle chipsets is exploited by remote, unauthenticated attackers using UDP packets to a server on port 9034, enabling remote execution of arbitrary commands. The attack involves injecting a shell command that downloads and executes a shell script on the compromised device. This script downloads binaries for various CPU architectures, such as ARM, MIPS, and SuperH, primarily from the Mirai malware family, turning the device into a botnet node.\n\nThe attack script connects to a malicious IP to download and execute malware, with threats mainly from Mirai, Gafgyt, and Mozi families. It also includes a new DDoS botnet called RedGoBot, developed in Golang. The script uses wget and curl to download botnet clients for different processor architectures. RedGoBot can perform DDoS attacks on various protocols, including HTTP, ICMP, TCP, UDP, VSE, and OpenVPN, upon receiving commands from the threat operator. Additionally, injected commands can write binary payloads to files for execution or reboot the targeted server to cause denial of service.","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"},{"id":"T1105","name":"Ingress Tool Transfer","tactics":["command-and-control"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Code Execution","mappingType":"secondary_impact","evidence":[],"comment":"The vulnerability in Realtek Jungle chipsets is exploited by remote, unauthenticated attackers using UDP packets to a server on port 9034, enabling remote execution of arbitrary commands. The attack involves injecting a shell command that downloads and executes a shell script on the compromised device. This script downloads binaries for various CPU architectures, such as ARM, MIPS, and SuperH, primarily from the Mirai malware family, turning the device into a botnet node.\n\nThe attack script connects to a malicious IP to download and execute malware, with threats mainly from Mirai, Gafgyt, and Mozi families. It also includes a new DDoS botnet called RedGoBot, developed in Golang. The script uses wget and curl to download botnet clients for different processor architectures. RedGoBot can perform DDoS attacks on various protocols, including HTTP, ICMP, TCP, UDP, VSE, and OpenVPN, upon receiving commands from the threat operator. Additionally, injected commands can write binary payloads to files for execution or reboot the targeted server to cause denial of service.","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"},{"id":"T1496","name":"Resource Hijacking","tactics":["impact"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Code Execution","mappingType":"secondary_impact","evidence":[],"comment":"The vulnerability in Realtek Jungle chipsets is exploited by remote, unauthenticated attackers using UDP packets to a server on port 9034, enabling remote execution of arbitrary commands. The attack involves injecting a shell command that downloads and executes a shell script on the compromised device. This script downloads binaries for various CPU architectures, such as ARM, MIPS, and SuperH, primarily from the Mirai malware family, turning the device into a botnet node.\n\nThe attack script connects to a malicious IP to download and execute malware, with threats mainly from Mirai, Gafgyt, and Mozi families. It also includes a new DDoS botnet called RedGoBot, developed in Golang. The script uses wget and curl to download botnet clients for different processor architectures. RedGoBot can perform DDoS attacks on various protocols, including HTTP, ICMP, TCP, UDP, VSE, and OpenVPN, upon receiving commands from the threat operator. Additionally, injected commands can write binary payloads to files for execution or reboot the targeted server to cause denial of service.","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"},{"id":"T1499","name":"Endpoint Denial of Service","tactics":["impact"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Code Execution","mappingType":"secondary_impact","evidence":[],"comment":"The vulnerability in Realtek Jungle chipsets is exploited by remote, unauthenticated attackers using UDP packets to a server on port 9034, enabling remote execution of arbitrary commands. The attack involves injecting a shell command that downloads and executes a shell script on the compromised device. This script downloads binaries for various CPU architectures, such as ARM, MIPS, and SuperH, primarily from the Mirai malware family, turning the device into a botnet node.\n\nThe attack script connects to a malicious IP to download and execute malware, with threats mainly from Mirai, Gafgyt, and Mozi families. It also includes a new DDoS botnet called RedGoBot, developed in Golang. The script uses wget and curl to download botnet clients for different processor architectures. RedGoBot can perform DDoS attacks on various protocols, including HTTP, ICMP, TCP, UDP, VSE, and OpenVPN, upon receiving commands from the threat operator. Additionally, injected commands can write binary payloads to files for execution or reboot the targeted server to cause denial of service.","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"},{"id":"T1569.002","name":"Service Execution","tactics":["execution"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Code Execution","mappingType":"secondary_impact","evidence":[],"comment":"The vulnerability in Realtek Jungle chipsets is exploited by remote, unauthenticated attackers using UDP packets to a server on port 9034, enabling remote execution of arbitrary commands. The attack involves injecting a shell command that downloads and executes a shell script on the compromised device. This script downloads binaries for various CPU architectures, such as ARM, MIPS, and SuperH, primarily from the Mirai malware family, turning the device into a botnet node.\n\nThe attack script connects to a malicious IP to download and execute malware, with threats mainly from Mirai, Gafgyt, and Mozi families. It also includes a new DDoS botnet called RedGoBot, developed in Golang. The script uses wget and curl to download botnet clients for different processor architectures. RedGoBot can perform DDoS attacks on various protocols, including HTTP, ICMP, TCP, UDP, VSE, and OpenVPN, upon receiving commands from the threat operator. Additionally, injected commands can write binary payloads to files for execution or reboot the targeted server to cause denial of service.","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2021-22037","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-22037","exploited":true,"exploitedSince":"2021-12-10","provenance":"source"},"exploits":[],"exploitSources":{"nuclei":[{"id":"CVE-2021-35394","name":"RealTek AP Router SDK - Arbitrary Command Injection","severity":"critical","path":"javascript/cves/2021/CVE-2021-35394.yaml","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/javascript/cves/2021/CVE-2021-35394.yaml"}],"provenance":"source"},"exploitRefs":["https://www.iot-inspector.com/blog/advisory-multiple-issues-realtek-sdk-iot-supply-chain"],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"source"},{"stage":"primary","techniques":["T1059"],"provenance":"source"},{"stage":"secondary","techniques":["T1569.002","T1071.001","T1105","T1496","T1499"],"provenance":"source"}],"timeline":[{"date":"2021-08-16","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-35394","provenance":"source"},{"date":"2021-08-27","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://blogs.juniper.net/en-us/threat-research/realtek-cve-2021-35394-exploited-in-the-wild","provenance":"source"},{"date":"2021-12-10","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2021-12-10","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-22037","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":116},"priority":{"score":69.9,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":0.0,"detail":"added 1889 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.99,"detail":"percentile 0.9996"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"1 NVD reference tagged Exploit; 1 nuclei template"},{"name":"Mentioned in OTX pulses","points":3.0,"detail":"50 pulses"},{"name":"CVSS severity","points":6.86,"detail":"base score 9.8"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}